The proposed research examines the nature and sequence of perimenopausal symptoms, their interaction with race, and the effect of diet and menopause transition on the skeletal and vascular systems. Finally, it evaluates a new marker of ovarian aging and important new information about the genetic determinants of bone mass before and after the menopause. This project is an extension of the investigators' previous and ongoing collaborative work in the area of menopause and menopause- related bone loss. It differs from and builds upon this prior research by focusing on changes occurring prior to the last menstrual period, and by focusing on African-Americans. The specific aims of this research are to: (1) examine whether there are racial differences in the epidemiology of menopause including age of menopause and age of inception and length of the perimenopause, (2) examine symptomatology and behavior related to menopause transitions, (3) study the effects of the menopause.transitions on bone mass and biochemical markers of bone turnover, (4) study the effects of allelic variation in the vitamin D receptor genotypes on baseline bone densities and rates of change during the menopause, (5) assess the utility of mullerian inhibing substance (MIS) as a new marker of ovarian aging, and (6) study the effects of the menopause transition on vascular wall compliance and thickness. We will recruit a community-based sample of 400 women (50% African- American) aged 45-49 who are either premenopausal (menses in past 3 months and no change in regularity) or early perimenopausal (menses in past 3 months with changes in regularity). Women who have been on hormone replacement therapy at any time in the previous 3 months will be ineligible at recruitment. After a 12- month recruitment period, subjects will be followed for 3.5 - 4.5 years (during this grant period) with annual clinic visits plus semi-annual blood samples and telephone interviews. Based on our existing longitudinal data, it is anticipated that two-thirds of the women will reach late perimenopause and one-third will become postmenopausal during this application period. Results of this study will provide important data with practical implications for the initiation and use of hormone replacement therapies.